openafs-client: add option for OpenAFS cache location

Our control plane servers generally have large ephemeral storage
attached at /opt; for many uses this is enough space that we don't
need to add extra cinder volumes for a reasonable cache (as we usually
do on mirror nodes; but there we create large caches for both openafs
and httpd reverse proxy whose needs exceed even what we get from
ephemeral storage).

Add an option to set the cache location, and use /opt for our new
static01.opendev.org server.

Change-Id: I16eed1734a0a7e855e27105931a131ce4dbd0793

playbooks/service-static.yaml

@@ -9,4 +9,5 @@
         - kdc04.openstack.org
     - role: openafs-client
       openafs_client_cache_size: "{{ afs_client_cache_size | default(50000000) }}" # 50GiB
+      openafs_client_cache_directory: '/opt/cache/openafs'
     - role: static

roles/openafs-client/README.rst

@@ -20,12 +20,17 @@ role has limited platform support.  Currently supported are
 .. zuul:rolevar:: openafs_client_cell
    :default: openstack.org
 
-   The default cell
+   The default cell.
 
 .. zuul:rolevar:: openafs_client_cache_size
    :default: 500000
 
-   The AFS client cache size, in kilobytes
+   The OpenAFS client cache size, in kilobytes.
+
+.. zuul:rolevar:: openafs_client_cache_directory
+   :default: /var/cache/openafs
+
+   The directory to store the OpenAFS cache files.
 
 .. zuul:rolevar:: openafs_client_yum_repo_url
    :default: ``https://tarballs.openstack.org/project-config/package-afs-centos7``

roles/openafs-client/defaults/main.yaml

@@ -1,2 +1,3 @@
 openafs_client_cell: 'openstack.org'
+openafs_client_cache_directory: '/var/cache/openafs'
 openafs_client_cache_size: 500000

roles/openafs-client/tasks/main.yaml

@@ -45,6 +45,15 @@
     - ThisCell
   become: yes
 
+- name: Ensure cache location directory
+  file:
+    path: '{{ openafs_client_cache_directory }}'
+    state: directory
+    owner: root
+    group: root
+    mode: 0700
+  become: yes
+
 - name: Setup OS specific openafs-client environment
   include_tasks: "{{ lookup('first_found', params) }}"
   vars:

roles/openafs-client/templates/cacheinfo.j2

@@ -1 +1 @@
-/afs:/var/cache/openafs:{{ openafs_client_cache_size }}
+/afs:{{ openafs_client_cache_directory }}:{{ openafs_client_cache_size }}